LONDON — For the first time, a police force has used evidence gathered by a scientific technique known as "genetic fingerprinting" to formally charge a suspect with a serious crime.
After a highly unusual investigation that included taking more than 5,500 blood and saliva samples from adult males residing in the immediate area of the crimes, Leicestershire County police late Sunday night charged a 27-year-old baker with the murder-rape of two teen-age girls.
The man charged, Colin Pitchfork, was held without bail after a brief court appearance in the city of Leicester, 100 miles north of London.
Although the technique has been questioned by civil libertarians, some forensic scientists view it as potentially the most significant breakthrough since the development of fingerprinting in solving crimes.
'It Was a Local Man'
Pitchfork's arrest came nearly four years after the first victim died and nine months after police began taking serum samples in an effort to revive an investigation that had gone cold for the lack of clues.
"The system we employed turned him up," Detective Superintendent Anthony Painter said. "We believed from the start that it was a local man."
While English legal constraints prevent public discussion of any specific details in the case, it is believed that forensic scientists were attempting to match the genetic fingerprints found in semen samples collected after the rape and murder of the victims.
Pitchfork resides in the village of Littlethorpe, one of three communities where police asked every male between 13 and 30 years of age to provide blood and saliva samples voluntarily.
Although 2 1/2 years separated the killings, which occurred near the small Midlands village of Enderby, the technique of isolating elements of the genetic structure in blood--a structure said to be as individually distinctive as a fingerprint--supported police suspicion that the same man committed both crimes.
Genetic fingerprinting also led directly to the release of a 17-year-old boy initially charged with one of the murders.
The laboratory testing technique was first developed by a Leicester University geneticist, Alex Jeffreys, who focused his attention on a bodily substance called DNA--deoxyribonucleic acid--found in the chromosomes of all living beings but in uniquely different patterns.
The arrangement of the series of bands that comprise the DNA is as individually specific as a fingerprint, with the chance of two persons having identical patterns estimated at between 30 billion and 100 billion to one, according to Jeffreys.
He says that the test is effective on dried blood as old as five years and on dried semen up to three years old.
Leicestershire police investigators said they resorted to blood and saliva sampling because evidence indicated that the murderer knew the paths and fields of the semi-rural area well. The small, stable and willing population in the three surrounding villages made such an investigation feasible.
A strong sense of community outrage among close-knit villagers and an effective police public relations campaign effectively overcame apprehensions among some residents that the tests were an invasion of their personal rights.
Painter said that 5,511 men had voluntarily provided the samples since January and that only one had refused.
"We made it clear from the start it was voluntary," Painter said. "He exercised his legal right."
Painter said efforts to conduct the few remaining tests had been suspended after Pitchfork's arrest.